This invention relates to the determination of the amount of oil in water flowing in a conduit, and more particularly to an apparatus for continuously monitoring such oil content.
Many techniques are currently in use for determining the content of oil in water. Among these are a variety of procedures including measurements of fluorescence, turbidity, conductivity, and the like. One of the known techniques has been to utilize carbon tetrachloride to extract the oil from a discrete sample of oil containing water, and then to subject the carbon tetrachloride to infrared analysis to determine the amount of oil extracted from the sample. That technique, however, because of its use of discrete samples, is considerably time consuming and provides only an intermittent view of the amount of oil contained in a flow of water.
Because of the present day interest in avoiding contamination of the earth's waters with oil, it has become increasingly important to be able to monitor a flow of water for oil content on a continuous flow basis so as to provide a greater assurance of accuracy, and to permit rapid automated responses to changes in the oil content, for example, actuation of diverter means to prevent discharge to the environment of water containing more than a permissible low level of oil content.
Automated, general purpose discrete sample analyzing apparatus have been devised in an effort to increase the speed of analysis of discrete samples and approximate continuous flow monitoring of the type with which this invention is concerned. One example is provided in U.S. Pat. No. 4,013,413 to K. K. Stewart, et al. Such apparatus requires relatively complex valving, sample taking probe actuation, and the like, making truly repeatable readings unlikely over any substantial period of time. Moreover, that apparatus does not provide for automatic referencing of the analyzer element, an important feature which is included in the continuous oil concentration monitor embodying this invention.